# algebra

Mr. Smith has 100 students in his Algebra classes. The grades of a quiz are normally distributed with a mean of 70 and a standard deviation of 4. Sally claims that 75 students scored between 66 and 74 on this quiz. Given that this is normally distributed, is Sally correct? Justify your answer using mathematical reasoning and your knowledge of normal distributions.

1. 👍 0
2. 👎 0
3. 👁 189
1. Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability between the two Z scores. Is it close to .75?

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Math

Top ten scores on a quiz in two classes are listed below Class A 100,100,100,90,95,85,92,98,92,88 class B 100,100,98,95,95,96,95,92,81,88 which statement is true concerning the data a. the mode is the same for both classes b. the

asked by Austin on May 19, 2014
2. ### Algebra

Mallory had an average of 87 on her first three algebra quizzes. She made the same score on the first two quizzes and 9 points higher on the third quiz. What was her grade on each quiz?

asked by Taylor on October 16, 2019
3. ### maths

out of 40 students,14 are taking english and 29 are taking chemistry.if 5 students are in both classes,how many are in neither class?how many students are in either classes?

asked by OBIRI on October 2, 2018
4. ### elementary statistics

A statistics professor is used to having a variance in his class grades of no more than 100. He feels that his current group of students is different, and so he examines a random sample of midterm grades (listed below). At 0.05

asked by David on November 30, 2013
5. ### statistics

Professor Smith conducted a class exercise in which students ran a computer program to generate random samples from a population that had a mean of 50 and a standard deviation of 9mm. Each of Smith's students took a random sample

asked by lauren on February 16, 2008
1. ### Quantitative methods

the mean and standard deviation of the grades of 500 students who took an maths exam were 69 and 7 respectively. if the grades have a bell shaped distribution, how many of these students received a grade of more than 83 marks?

asked by lisa on April 7, 2011
2. ### Logic

Mrs. Orlof teaches two history classes, one in the morning and one in the afternoon. Yesterday she gave the same test to both classes. Anyone who failed the test must take a retest. Since a greater percentage of students who took

asked by Tammy on August 12, 2012
3. ### math

In a survey of 150 students, 90 were taking algebra, and 30 taking biology. a. what is the least number of students who could have been taking both classes? b. what is the greatest number of students who could be taking both

asked by math student on September 14, 2013
4. ### English

posted by rfvv Saturday, September 2, 2017 at 2:06am. 1. I'll get you Mr. Smith. 2. I'll put you through to Mr. Smith. 3. I'll connect you to Mr. smith. 4. I'll transfer your call to Mr. Smith. (Are they grammatical and similar in

asked by rfvv on September 4, 2017
5. ### Algebra

Mr. Smith has 100 students in his Algebra classes. The grades of a quiz are normally distributed with a mean of 70 and a standard deviation of 4. Sally claims that 75 students scored between 66 and 74 on this quiz. Given that this

asked by Help is needed on March 2, 2015